Your tiny-batch stickers reflect of local wage levels more than EU regulation. VAT will be part of it too.
But on safety compliance, the electrical crap that Temu (et al) rain on our countries is a fire hazard. It shouldn't be controversial that goods that don't meet EU standards be barred.
When sales are direct B2C, the EU can't retroactively (or prospectively) stop them, nor recall sent units, not in the way they can when a container rocks up with tens of thousands of units that turn out to be dodgy.
I don't know what the answer is. Making Temu (et al) liable for goods' compliance —in the way importers are— seems like a sensible start.